Fuel log of recycled materials and methods of manufacture

ABSTRACT

A combustible solid fuel source in the form of a log is formed from a base material of a cellulosic or fibrous organic material which is compressed in a screw press up to 20,000 pounds to a density in the range 50 to 85 lbs/cu ft. The log is cut to length and partly immersed in a bath of a combustible vegetable oil which absorbed into the base material as it slightly expands such that the content of oil is less than 50% by weight and generally of the order of 30% where the log is dry to the touch and the oil is entirely contained without the need for an external covering of wax or the like. The base material is selected from lumber, agricultural waste or animal waste to contain fibers such that the content of ash when the source has been fully combusted is generally less than 2% by weight with very little contaminants.

This invention relates to fuel logs and other fuel elements made of organic fibrous materials mixed with a combustible oil. The term “log” is intended herein to include both bodies shaped and arranged for burning in a fire place or stove and bodies shaped for burning in other locations such as industrial heating systems and power station where coal has been a primary heat source.

This application relates to the subject matter disclosed in U.S. patent application Ser. No. 12/202,567 filed Sep. 2, 2008 entitled BIOMASS PRESSURE LIQUID RECOVERY SYSTEM, the disclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

Manufactured fire logs are normally used as substitutes for cordwood in fireplace and small wood stoves during power outages for example or simply for pleasure. Synthetic fire logs can be purchased one at the time and are generally wrapped neatly, making them more attractive than natural wood blocks to the occasional user. Their clean-burning characteristics are advantageous over natural wood, and therefore these logs are also preferred by the environment-conscious people.

Also in a related field, power stations are commonly fueled by coal and it is highly desirable to replace this fuel source with a renewable energy source from recycled materials to avoid depletion of fossil fuels and to avoid the contaminants commonly present in coal.

Fire logs currently available to consumers are dividable in two types. The first type contains about 40-60% wax with the remaining portion being sawdust, wood chips or wood shavings. The second type contains wood fibers in various forms impregnated with vegetable, animal or petroleum oil. In both types, the wax and the oil are the primary source of heat with the fibrous material being the substratum of the product. Typically, fire logs have a heat capacity of almost twice as much as cordwood and their moisture contents are much lower, providing a more complete combustion.

U.S. Pat. No. 1,484,302 issued to C. Y. Garrett on Feb. 19, 1924, discloses a combustible block which is used as a fire kindling material. The block is made of pieces of wood, or wood pulp impregnated with resin and coated with wax. Different compositions are proposed. For example, the wood shavings content is 25% to 75% and the resin content is 25% to 58%.

U.S. Pat. No. 4,120,666 issued to S. R. Lange on Oct. 17, 1978, discloses an artificial fireplace log made of shredded paper and wax. The preferred proportions are 32% to 45% paper and 55% to 68% wax.

U.S. Pat. No. 4,326,854 issued to J. D. Tanner on Apr. 27, 1982 discloses a synthetic fire log made of 35%-40% by weight of cellulosic material such as wood or paper, a suitable liquid combustible by-product such as vegetable or animal oil, and a gelling agent to solidify the liquid by-product therein.

U.S. Pat. No. 5,244,472 issued to J. J. Simmons on Sep. 14, 1993 discloses a method to manufacture cellulosic fuel from wood chips impregnated with vegetable oil. The wood chips are immersed in hot vegetable oil and heated to reduce the moisture content in the wood chips to less than 10%, and until the oil content of the wood chips is between 10% to about 30%.

U.S. Pat. No. 6,017,373 issued to G. Frisch on Jan. 25, 2000 discloses an artificial log which contains coriander seeds to create a crackling sound. The log is made of 35% to 55% by weight of a combustible material such as wood chips, sawdust, cardboard, and 45% to 65% by weight of a flammable wax binder material such as paraffin or stearic acids derived from vegetables.

U.S. Pat. No. 6,458,177 issued to M. Cox on Oct. 1, 2002, discloses a synthetic fire logs made of wood waste and wax in a ratio of 40:60.

Emissions from residential wood stoves, furnaces and fireplaces contribute significantly to particulate matters (PM) and volatile organic compounds (VOC) released in the air. The adverse effects of these and other pollutants on human health and on the environment is well known.

The type of synthetic fire logs which is of interest herein contains primarily fibrous organic materials, and vegetable oil as the primary fuel element. It is known that vegetable oil is more combustible than wood resins and—wax, and therefore the oil burns more efficiently with less pollution than natural wood or paraffin wax. Therefore, it is believed that air polluting emissions, including particulate matters, carbon oxides, benzene, an formaldehyde, can be reduced significantly by burning manufactured fire logs containing vegetable oil, instead of cordwood or synthetic logs containing petroleum oils or paraffin wax.

PCT Published Patent Application 2005/010132 published Feb. 3 2005 by Bonnell-Rickard et al discloses an arrangement intended to infuse as much vegetable oil as possible in cellulosic material from recycled paper to make synthetic fire logs. Vegetable oils and especially used cooking oils are easily available from restaurants and hotels for examples, and therefore this product is a preferred ingredient for making synthetic fire logs. The composition of the fire log comprises recyclable organic fibers from recycled paper over-saturated with vegetable cooking oil. The vegetable oil is infused into the organic fibers and is contained and sealed therein by an envelope made of the vegetable wax. The proportion of vegetable oil is 65%-75% by weight. The vegetable oil is used vegetable cooking oil. The organic fibrous substratum thereof represents about between 20%-30% by weight and consists of compressed paper-based products such as cardboard, newsprint, and other recyclable paper. A vegetable wax envelope is provided which represents about between 1-5% of the weight of the log.

This is obtained by compressing cellulosic pulp by about ⅓ of its initial volume to expel water to provide a water content of roughly 15%. The log so formed is then heated to dry it to a water content of about 1%. The heating takes of course a high energy use so that the economics of the process are highly questionable.

This arrangement contains a very high proportion of oil which therefore requires to be contained by a wax coating. The use of paper as a primary source is unsuitable as it contains clay as a binder which leads to a high quantity of ash and also contains undesirable toxins.

SUMMARY OF THE INVENTION

It is one object of the present invention to provide a combustible solid which has a high calorific value.

According to the present invention there is provided a fuel source comprising:

a base formed of a cellulosic or fibrous organic material which is compressed to a density of at least 50 lbs/cu ft;

a combustible oil absorbed into the base material such that the content of oil is less than 50% by weight;

the base material being arranged such that the content of ash when the source has been fully combusted is less than 10% by weight.

Preferably the oil content is less than 35%.

Preferably the density of the base material lies in the range 50 to 85 lbs/cu ft.

Preferably the oil is a vegetable oil.

Preferably the ash content is less than 2%.

Preferably the quantity of oil is arranged such that the amount of oil is substantially the maximum which can be absorbed while the oil has no tendency to escape from the base material.

Preferably the base material containing the oil is dry to the touch.

Preferably the base material has an exterior surface which is substantially free from an exterior coating.

Preferably the base material contains a quantity of fibers from recycled paper which relatively low so as to avoid the presence of toxins generally present in paper.

Preferably the base material is compressed to a moisture content of less than 15%.

Preferably the base material has a calorific value of greater than 4,000 BTU/lb and preferably greater than or of the order of 5,000 BTU/lb and generally in the range 4000 to 10,000.

According to a second aspect of the present invention there is provided method for forming a combustible solid fuel source comprising:

providing a base formed of a cellulosic or fibrous organic material;

compressing the base material to a density of at least 50 lbs/cu ft;

the compression being arranged to reduce the moisture content of the base material to less than 15%;

and contacting the base material with a combustible oil so as to cause the oil to be absorbed into the base material such that the content of oil is less than 50% by weight.

Preferably the base material after compression is contacted by the oil substantially without the addition of heat to the base material.

Preferably the base material has a moisture content prior to compression of at least 25%.

19. The method according to claim 11 wherein moisture and oil are expelled from the base material during the compression.

The arrangement therefore described hereinafter provides a fuel source formed from any cellulose or fibrous organic based product that has been mechanically processed or compressed, such as in a press or screw compression mechanical device, that has been supplemented with a higher BTU organic oil. The oil may be processed or not. The resulting BTU content is significantly higher than the host material. This can include but is not limited to agricultural and biomass waste or surplus products such as flax seed oil, canola oil, or biodiesel or hydrocarbons or coal oil extracts or any manner or higher BTU content fuels added.

The fuel material defined by the source can be in the form of a log for use in a home or similar situation. Such a log may have a diameter or transverse dimension roughly in the range 4 to 6 inches and may have a length selected according to the end use since the logs can be cut to a required length. Typically a home use log will be of the order of 12 to 24 inches. Longer lengths can be used to assist in transportation for example where the log length is 7.5 feet to allow the logs to be stacked lengthwise across a typical transportation container of 8 feet.

Where the intention is to feed an existing furnace such as a coal fired furnace or a power station, the logs may be ground up to any required shape and size to feed the known systems. The grinding action may generate smaller pieces for feeding using the conventional feeding conveyor systems or may reduce the logs to a powder for air flow feeding or fluidized bed technology. The formation of log shape, that is a continuous body of constant dimension, is particularly suitable using available compression systems for example of the type described herein. However other compression systems forming other shapes may be used.

BRIEF DESCRIPTION OF THE DRAWINGS

One embodiment of the invention will now be described in conjunction with the accompanying drawings in which:

FIG. 1 is a schematic layout of a system for manufacturing a solid fuel source according to the present invention.

FIG. 2 is a schematic side elevational view of a biomass compactor for use in the method of FIG. 1.

FIG. 3 is a schematic top plan view of the biomass compactor of FIG. 2.

FIG. 4 is an end elevational view of the forming barrel taken along the lines 4-4 of the biomass compactor of FIG. 1.

In the drawings like characters of reference indicate corresponding parts in the different figures.

DETAILED DESCRIPTION

In FIG. 1 is shown a method for forming a combustible solid fuel source in the form of logs, briquettes and pellets and the like. The method includes supplying a biomass supply 100 which provides a base material of a fibrous or cellulosic material.

Any fibrous or vegetable material can be used and examples of such materials include wood waste and sawdust from the lumber industry, any waste vegetable material from agriculture such as wheat straw and chaff, corn cobs, rice husks, and animal waste such as horse or cow manure, and hog waste. The supply may form part of a larger processing system which takes the waste and removes liquid for re-use and compresses the remaining solids to form the compressed base materials. Thus the supply can be taken from animal plants such as hog plants where the manure is currently a problem and is processed to provide fuel. Horse manure is particularly suitable as it contains much fibrous material which remains undigested and thus is generally of large volume and low water content.

Wood products which are high in oil content can be used such as cedar and palm in that the oil can be initially extracted by the compression system described herein and then oil can be re-absorbed after the compression is removed. The same or a different oil can be absorbed. Typically the cedar oil is unsuitable in that it contains contaminants which are unsuitable to be burnt in the end product.

Thus the system can be used to clean up palm waste which is typically difficult to use because of its high oil content.

The biomass material is taken from the supply and passed through a compression system 101 for compressing the base material. The compression system can be of the type described in detail hereinafter. However a simple press system can be used of a conventional nature. The compression however must be relatively high so that screw type systems are preferred since these can generate the high pressures and high temperatures required to expel excess moisture and to increase the density to required levels.

The screw system described hereinafter allows compression of the biomass materials described to a density of at least 50 lbs/cu ft and generally in the range 50 to 65 lbs/cu ft. Thus for example a fibrous mass containing 25% water content at a density of the order of 16 lbs/cu ft can be compressed to a mass at a density of at least 50 lbs/cu ft and as much as 85 lbs/cu ft and a moisture content of less than 2%. Thus the compression system 101 includes a water expulsion system 102 as a part of the compression system. Typically no heat is added for a drying action as this requires additional energy costs. However some initial separation of water and solid material may occur using a mechanical separation system to reduce initial moisture content to a lower initial value.

A combustible oil is provided in a supply 104 which may be passed through a treatment system 105 to remove contaminants or to add additives such as scenting materials. Contaminants from cooking oil can be removed where the supply is a used cooking oil using techniques which are well known.

The compressed solid material from the compression system 101 is contacted with the oil in a mixer 106. This can be a simple mixing bath where the solid compressed bodies are passed through the bath on a conveyor or are merely dumped into the bath and removed by a lifting system.

This causes the oil to be absorbed into the base material such that the content of oil is less than 50% by weight, les than 35% and generally of the order of 30%. This level of absorption is achieved typically by the bodies sitting in the bath partly immersed in the oil. For example the logs may be carried on a screen type conveyor into a bath of the oil such that approximately one half of the log is immersed leaving an upper half exposed. The process can be controlled by changing the rate of forwarding movement of the conveyor so that the log is half immersed for a period of time such that the oil can be observed to wick up to the top of the log. When this has occurred, a sufficient quantity of oil has been absorbed allowing the conveyor to carry the log out of the bath where it can be blown dry of any sitting oil by an air stream and then can be allowed to sit and drain any excess from the surface. The oil which has been absorbed by the wicking action of the fibers remains contained and does not leak no matter how long the log is allowed to sit. No covering of wax or other encapsulating material is required. Although a wrapping of paper or other material may be provided for presentation to the public. It will be appreciated that the compression process described hereinafter causes initial compression under high load thus reducing the volume to a maximum extent while the compression remains in effect. At this stage substantially no air spaces remain. However when the compression is removed the body will slightly expand allowing the fibers to move slightly apart so that the oil can enter into the spaces thus formed between the fibers and is actively drawn into these spaces by the expansion effect.

No heating for drying of the compressed base materials is required although the oil may be warmed to aid absorption. The compression of the material to the above stated levels allows the oil to be taken up to a percentage by weight typically of the order of 30% without any additional step to increase take up. Leaving the material in the bath for a longer time typically does not increase take up. The oil is absorbed through the whole body of the material so that it is take up to a common level throughout the structure.

The oil is a preferably a vegetable oil as it is a renewable resource but in some cases other oils such as coal oil or petroleum based oils can be used. Although these are less suitable in view of the content of contaminants unless the contaminants are removed in a preliminary process.

After the oil is absorbed, the material including the oil is removed from the bath and placed in a location 107 to drain off any surface oil for collection and return to the bath. After draining for a period sufficient to allow any surface oil to fall off, the quantity of oil is arranged within the material such that the oil has no tendency to escape from the base material. That is the oil remains captured within the structure for an extended period and such that the base material containing the oil is dry to the touch.

The drained base material containing the oil is then moved to a packaging system 108 where it can be wrapped in a suitable covering such as wax paper. The material itself therefore has an exterior surface which is wholly or at least substantially free from an exterior coating such as wax since the oil remains encapsulated without such a coating. The wrapping material is used simply for packaging of logs for home use so that they are suitable presented to the home user. In a situation where the material in briquette or pellet form is to be used in bulk for example in a furnace, no wrapping is required. Bulk transport systems can be used as are well known to persons skilled in this art.

One example of a compression system which can achieve the above conditions for the base material is shown in FIGS. 2, 3 and 4, where generally the biomass compactor which includes a primary cylinder or barrel 10 which acts as a compression barrel within which the biomass material is compressed by an auger 11 within the barrel 10. The barrel 10 has an inlet 12 in one side. Barrel 12 has a cylindrical peripheral wall 13, a first closed end 14 and a second open end 15 through which the compressed materials are discharged.

The auger 11 comprises a series of independent flights so that each flight has a start position and an end position where the ends of the flights are spaced longitudinally along the auger shaft. This forms a multi-start auger system in which the material entering the barrel can engage into the position between the individual flights to be carried by the flights during their movement caused by rotation of the auger shaft 15. The auger shaft 15 is formed from a sleeve 16 and an inner shaft 17 on which the sleeve 16 is mounted. The shaft 17 is carried in bearings 18 and 19 and is driven by a motor 20 communicating drive to an input pulley 21. Thus the shaft extends coaxially with the cylinder 10 and the sleeve 16 is carried on the outside surface of the shaft 17 so that the sleeve and the shaft project into the interior of the barrel and axially along the barrel 10 to the discharge end 15. The auger flights are mounted on the outside of the sleeve 16 and extend from the outside surface of the sleeve 16 to the cylindrical inside surface of the barrel 10. This provides a spacing between the outside surface of the sleeve and the inside surface of the barrel 10 which is of the order of 2 inches in height. Typically the sleeve has an outside diameter of the order of 4 inches so that the inside of the barrel has a diameter of the order of 8 inches. These dimensions are of course only typical and other dimensions can be used particularly when the structure is scaled upwardly to larger dimensions for transporting and compressing larger quantities of material.

The inlet 12 of the barrel 10 is supplied by a feed system generally indicated at 25 which includes a tube 26 which is fed from a hopper 27. The tube 26 extends horizontally away from one side of the barrel 10 and the hopper 27 is mounted on an outer end of the tube so as to provide feed material to be fed into the tube and along the tube into the inlet 12. The hopper 27 is generally rectangular with side walls 28 and 29 and end walls 30 and 31 with the end walls at right angles to the tube 26. At the bottom, the hopper converges inwardly to a base 33 centrally of the side walls 28 and 29 and generally aligned with the tube 26. An auger 34 is mounted at the base so that the materials falling to the base and converge inwardly to the base are carried along the base and into the tube 26 by the auger 34 and the flights thereon. The auger 34 is driven by a motor 35 through a drive chain 36 at the end 30 of the hopper. The auger 34 is mounted in bearings 37 and 38 at the end walls 30 and 31 and extends up to the entrance into the barrel 10 so as to compress the materials from the hopper and feed the materials into the auger flights to ensure a smooth continuous flow of the material into the auger flights on the shaft 15.

As many of the materials to be supplied into the barrel 10 for compression are fibrous, bridging is typically a problem within the hopper so that rotating members 40 and 41 are provided within the hopper above the auger 34 and on opposite sides of the auger 34. The rotating members 40 and 41 comprise shafts 42 carried in bearings 43 and driven by a motor 44 through a chain drive system 55. The rotary members 42 carry fingers or blades 56 projecting outwardly from the bars 42 for engaging into the material.

Typically the auger 34 rotates at an angular rate which is variable to control an input speed whereas the rotating members 40 and 41 which are not intended to carry out any driving action rotate at a slow rate at the order of 5 to 10 RPM.

The auger 11 carried on the shaft 15 carries, as previously explained, a plurality of auger flights. In the embodiments shown there are four such auger flights indicated at 11A, 11B, 11C and 11D. Each of these auger flights extends to an end 11E at the discharge from the barrel 10. Each of these auger flights has attached thereto a tip portion 11F at or adjacent the end 11E. This tip portion is formed of a wear resistant material such as carbide. As shown in FIG. 3, the ends 11E and the tip portions 11F project into a forming barrel 45 so that they project beyond an end wall 46 of the barrel 10 and thus provide a short portion which is proud of the end wall 46 and projects into the interior of the forming barrel 45.

Each of the tips 11F has a leading end 11G and a trailing end 11H. The tips are mounted on the auger flights so that the leading ends 11G all lie substantially in a common plane radial to the axis of the shaft 15. Thus the leading edges of the tips in the clockwise direction of rotation of the auger 11 as shown in FIG. 4 lie in a first plane radial to the axis of the shaft and the trailing edges 11H all lie in a second plane at radial of the axis. The second plane radial of the axis of the edges 11H is arranged to be axially advanced further into the forming barrel than the leading edges. In this way the tips form wiping blades which wipe over the material sitting in the barrel 45 so as to push against the rear surface of that material in a wiping action to smooth the material and to apply compressive force against the material to force the material along the barrel 45.

Thus as the auger 11 rotates, each flight carries material forwardly and discharges it into the barrel 45. That material as it is discharged is then wiped and smoothed by the action of the tips. This arrangement has been found to provide an effective action in compressing and squeezing the materials to apply high compressive forces which also significantly increase the temperature within the material at this location.

The effect of the multi-start auger together with the tips can apply a pressure up to 20,000 psi within the material at the entrance to the forming barrel 45. At the same time the temperature is typically elevated to a temperature of the order of 400° F. This high compression and high temperature acts to evaporate liquids and moisture within the material so that the gases so formed are driven off from the material.

As best shown in FIG. 4, the barrel 10 has a circular opening 10A at the discharge end which emerges into the barrel 45. The barrel 45 is of increased transverse dimension so that a space is formed between the imaginary cylinder defined by the outside edge of the opening 10A and the inside surface 45B of the barrel 45. Thus the material which is fed forwardly by the auger 11 on the shaft 15 emerges through the annular space around the shaft 15 and inside the opening 10A of the barrel 10 and that material is forced axially as well as outwardly into the space inside of the wall of the barrel 45. The area beyond the end of the shaft 15 is filled by a shaft extension portion 15A which is coaxial with the shaft 15 and of the same diameter and extends into the barrel 45 along its full length. The extension portion 15A is stationary and has an end 15B butting against the end of the shaft 15 at the end of the auger at the location just inside the barrel 45.

The previously explained wiping action carried out by the tips 11 F acts to apply pressure onto the material forcing it into a generally cylindrical area beyond the annular space and outwardly of the annular space to fill the whole of the interior of the barrel 45 outside the extension portion 15A.

This generates a compressed mass which is generally cylindrical with an inner surface defined by the outer surface of the cylindrical extension portion 15A.

Thus the mass formed in the compression is cylindrical with a distance D from the inside surface to the wall of the barrel 45 which is of the order of 2.0 inches. In this way the distance of any point in the compressed mass to the slotted wall of the barrel is relatively small and generally less than 3.0 inches so that gases and vapour and liquid can readily escape under compression.

The barrel 45 is polygonal in shape formed by wall portions 45A. In the example shown the barrel is octagonal with the wall portions of equal width. However other shapes can be used including square barrels and irregular shaped polygonal barrels.

The wall portions 45A are each defined by a series of parallel longitudinally extending bars 47 which lie in a common plane of the wall portion 46. The bars are supplied with a support system which holds the bars at a pre determined spacing which is typically of the order of 0.030 inch. The bars are triangular in shape with a flat face facing inwardly and an apex facing outwardly to provide sufficient strength for the bar while allowing a narrow slot at the face of the wall which faces inwardly.

Such structures are commonly available and are widely used in the oil industry under the trade name “Wedge-Wire”. Such materials are supplied with the ability to withstand significant outward forces while maintaining the narrow gap between each bar and the next bar. The bars extend along the full length of the chamber 45 from the end wall 46 through to a discharge end 50 of the forming chamber. The bars are supported by peripheral ribs 51 which are located at spaced positions along the length of the bar. Each rib 51 forms a peripheral flange extending around the full periphery of the barrel 45 so as to provide a fully surrounding band which prevents the significant forces within the barrel 45 from bowing the bars 47 outwardly.

The ribs 51 are continuous around the bars 47 so that outward stresses from the bars are communicated into tension in the ribs. An inside edge of the ribs engages the outside tip of the bars 47 to hold the tips against outward movement. The ribs can are welded at spaced positions along the bars.

The ribs are formed from sheet metal with the inside edge in contact with the bars and an outside edge spaced outwardly therefrom. In this way the ribs interfere with the exit of gases and liquid to the minimum extent.

Around the forming barrel 45 is provided a collection chamber 57 which is formed from a peripheral wall 58 and end walls 59 which contain the whole of the forming barrel such that the gases and liquid escaping are contained within the outside container 57 and can drain to a discharge opening 60 for collection. A vacuum can be applied at the discharge 60 to draw off the gases so that they can discharged safely or can be collected if valuable. In this way oils and other valuables excreted from the compressed materials can be collected for processing and sale. In this way the environment within the area surrounding the device can be kept free from contaminants exiting from the forming barrel.

An end plate 62 is provided on the end of the forming barrel and provides an orifice 63 through which the materials are discharged. The end plate 62 can be adjusted so as to change the dimensions of the orifice so that the plate provides a back pressure on the materials being forced through the forming barrel. This is particularly desirable at start-up in order to commence the application of back pressure through the forming barrel and into the compression barrel. Once the back pressure is developed, the friction between the materials and the wall of the forming barrel maintain that back pressure at a required level so as to generate the required pressures within the material.

Typically the shaft can be driven at a rate in the range 50 to 400 RPM depending on size. This rate can of course be varied within this range to control the pressures within the system. Other parameters can be varied to control the conditions within the system.

Typically the machine can be controlled so as to generate pressures in the range 1000 TO 20,000 psi and temperatures in the range 250 to 450 degrees F. Control of the system is primarily managed by measuring the temperature by a suitable sensor at the main compaction area at the tips of the auger and by measuring pressure within the compaction zone obtained by maintaining a resultant density in the range 50 to 65 lbs/cu ft.

In order to provide a sufficient throughput of material, the space between the extension portion 15A and the wall of forming barrel 45 is generally of the order of 2 to 3 inches in transverse dimension. However this total area of the cylindrical shape is too great in most cases to form an acceptable product which can be used in subsequent combustion processes. In order to manufacture combustion products of a desired transverse dimension, divider walls 66 are provided within the forming barrel which divides the total area into smaller separate areas with the materials being separated at a leading edge 68 of the dividing walls. This leading edge is located immediately downstream of the trailing edge 11H of the tips of the auger. The dividing walls are formed of sheet metal so as to reduce friction and allow the compressed materials to slide along the surfaces of the dividing walls and along the surfaces of the bars 47.

In FIG. 2 is shown an additional component 70 which is mounted beyond the exit gate 62 defined by the plate and this component forms a long tube through which the materials emerge so as to provide a cooling action. The structure can be formed of aluminium to ensure the extraction of significant quantities of heat so that the emerging compressed materials are sufficiently cooled for handling.

As an alternative, the forming barrel defined by the bars 47 can be removed from the end wall of the compression barrel and replaced by a simple tubular forming member defined by the component 70. The forming barrel 45 can be removed and replaced by a forming barrel defined by the component 70 in the event that the materials are sufficiently dry and free from oil to remove the necessity for extraction of such materials through the bars 47. However the forming barrel used has basically the same arrangements and characteristics as that previously described except that it is formed from the same tubular structure. Thus it co-operates with the tips of the auger as previously described and thus it includes dividing walls as previously described. In this case the forming barrel defined by the component 70 is longer since it carries out both the functions of forming and of cooling.

The apparatus uses primarily stainless steel components due to the high acid content of many of the biomass feed stock materials it can be used to de-water.

Animal wastes, oil seed plant wastes and other biomass feed stock with moisture contents up to 50% can be reduced to solids exhibiting very low moisture content. In order to achieve this, the pressure within the entrance to the forming barrel is typically of the order of 20,000 PSI. The resulted solids are appropriate for burning in a down draft gasifier or other conventional combustion system and typically such systems require a density of the compressed product of the order of 50 lbs. per cubic foot.

As shown the construction uses four auger flights and therefore includes four tips. However this may be reduced to three or increased as required. The use of multiple tips in this manner permits faster throughput while minimizing side thrust. As the flights are spaced around the axis, this spreads the side to side forces generated by the forwarding of the material around the axis.

The auger produces a hollow cylindrical compacted shape permitting liquid to leave the biomass compressed product at a very high rate. This produces a large volume of dewater material with reduced energy costs. Liquid, air and steam in the feedstock will migrate the short distance from the outside edge of the auger at the tips 11F and from the outside of the extension portion 15A to the slots between the bars where it is released. It will be appreciated that the significant point of compression and heating occurs at the tips of the auger flights where the material is pushed into and applied onto existing material within the forming barrel. At this location, therefore, the maximum heating action occurs as the compression effect is maximized.

Typical materials which can be processed include animal waste including poultry, cow and hog manure and even including sewage waste from households. The liquid extracted can be used as fertilizer. The solids material in the compacted shapes can be used as a combustion fuel.

The temperature of compression which generally reaches of the order of 400 degrees F. acts to sterilize pathogens.

Other materials can be processed including various plant products. One process includes growing hemp and similar plants on contaminated land which act to draw out the contaminants, following which the plant material is compressed in the system described above to extract oil while the contaminants remain in the compacted solids and can be extracted by combustion while using the heat generated. Such contaminants can include various metals which can be extracted and valuable metals collected.

Another process involves waste paper where the compaction can be used to extract the liquid content including ink, the compacted solids formed into a fuel product which is used in a combustion system and remaining clay from the paper being collected in the ash. Thus all of the components of the waste paper are either recovered or used to generate heat as a fuel.

These processes are enabled by the high level of liquid content which is allowed in the system and by the efficient use of energy to drive the system to effect the compaction.

Since various modifications can be made in my invention as herein above described, and many apparently widely different embodiments of same made within the spirit and scope of the claims without department from such spirit and scope, it is intended that all matter contained in the accompanying specification shall be interpreted as illustrative only and not in a limiting sense. 

1. A combustible solid fuel source comprising: a base material formed of a cellulosic or fibrous organic material which is compressed to a density of at least 50 lbs/cu ft; a combustible oil absorbed into the base material such that the content of oil is less than 50% by weight; the base material being arranged such that the content of ash when the source has been fully combusted is less than 10% by weight.
 2. The fuel source according to claim 1 wherein the oil content is less than 35%.
 3. The fuel source according to claim 1 wherein the density of the base material lies in the range 50 to 85 lbs/cu ft.
 4. The fuel source according to claim 1 wherein the oil is a vegetable oil.
 5. The fuel source according to claim 1 wherein the ash content is less than 2%.
 6. The fuel source according to claim 1 wherein the quantity of oil is arranged such that the amount of oil is substantially the maximum which can be absorbed while the oil has no tendency to escape from the base material.
 7. The fuel source according to claim 1 wherein the base material containing the oil is dry to the touch.
 8. The fuel source according to claim 1 wherein the base material has an exterior surface which is substantially free from an exterior coating.
 9. The fuel source according to claim 1 having a calorific value of greater than 4,000 BTU/lb.
 10. The fuel source according to claim 1 having a calorific value in the range 4,000 BTU/lb to 10,000 BTU/lb.
 11. A method for forming a combustible solid fuel source comprising: providing a base formed of a cellulosic or fibrous organic material; compressing the base material to a density of at least 50 lbs/cu ft; the compression being arranged to reduce the moisture content of the base material to less than 15%; and contacting the base material with a combustible oil so as to cause the oil to be absorbed into the base material such that the content of oil is less than 50% by weight.
 12. The method according to claim 11 wherein the oil content is less than 35%.
 13. The method according to claim 11 wherein the oil content is substantially equal to 30%.
 14. The method according to claim 11 wherein the density of the base material lies in the range 50 to 85 lbs/cu ft.
 15. The method according to claim 11 wherein the quantity of oil is arranged such that the amount of oil is substantially the maximum which can be absorbed while such that the oil has no tendency to escape from the base material.
 16. The method according to claim 11 wherein the oil is absorbed into the base material by dipping the base material into a bath of the oil leaving a top part of the base material exposed and by allowing the oil to wick to the top part of the base material.
 17. The method according to claim 11 wherein the base material after compression is contacted by the oil substantially without the addition of heat to the base material.
 18. The method according to claim 11 wherein the base material has a moisture content prior to compression of at least 25%.
 19. The method according to claim 11 wherein moisture and oil are expelled from the base material during the compression. 